Power management is desirable for desktop personal computers and workstations because a typical desktop computer system can consume several hundred watts of power per hour when it is turned on, whether or not it is being used. This energy consumption can be quite expensive, particularly in the context of large companies and other institutions that may have hundreds or even thousands of desktop computer systems turned on both day and night. One way to reduce power consumption is to power manage the computer system by, for example, turning off peripheral devices that are not in use or slow down the processes that are running on the computer.
Energy Star (EStar) guidelines are power management guidelines issued by the U.S. Government's Environmental Protection Agency (EPA). EStar guidelines exist for many products, including desktop computers. EStar power management guidelines require specified reduction in power within a specified time for a computer system when no keyboard or mouse activity has been detected.
As stated above, reduction in power consumption of peripheral devices is one way to improve power saving. Integrated drive electronics (IDE) is a type of hardware interface widely used to connect peripherals such as hard disks, CD-ROMs and tape drives to a desktop computer. Typically, two Enhanced IDE (EIDE) sockets are built onto the motherboard, and each socket connects to two peripheral devices via a 40-pin ribbon cable. Since peripheral devices are connected via the IDE, it is useful to control power to the peripheral devices via the IDE.